Montana ·
Bighorn River Fly Fishing Report - June 21, 2026
BIGHORN RIVER
ReportJUN 21 — 28, 2026
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Flow
1520CFS
Bighorn R bl Yellowtail Afterbay Dam nr St. Xavier
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Water Temp
—
Updated 2026-06-20
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Weather
53–77°F
Chance Rain Showers
💧
Clarity
Clear
Check post-storm
Flow is sitting at a very fishable 1,520 CFS with a gauge height of 59.43 ft, putting the Bighorn in prime shape with fish stacked in predictable feeding lanes. Water temps in the 50–55°F range have trout actively feeding throughout the day, with the best window running late morning into evening.
What's Working — Hot Flies
Tungsten Split Case Nymph - PMD #20
#20
Split Case - PMD #14
#14
Stealth Link Mercer - PMD #20
#20
Juju Baetis Tungsten #22
#22
Parachute - Blue Wing Olive #22
#22
Corn-fed Caddis (CDC) Tan #20
#20
Egan's Thread Frenchie Jig - Olive #12
#12
Egan's Frenchie #12
#12
Bionic Ant 2.0 - Black #16
#16
Roza's World Spain Perdigon Barbless #18 - 32
#18
Olsen's Hare's Ear Blowtorch Barbless #20 - 28
#20
Black Zebra Midge(TBH) #20
#20
Hatch Chart
| Insect | Size | Activity | Prime Time |
|---|---|---|---|
| Pale Morning Dun (PMD) | 16–20 | Heavy | 11 AM - 3 PM |
| Blue-Winged Olive (Baetis) | 20–22 | Moderate | 9 AM - 12 PM |
| Caddis | 16–20 | Moderate | 4 PM - 7 PM |
| Midge | 20–24 | Light | 7 AM - 10 AM |
| Terrestrials (Ants) | 14–16 | Light | 1 PM - 5 PM |
Best Time Window
- 8 AM - 11 AM: Midge and BWO nymphing in the riffles and tailouts before the PMD hatch kicks in.
- 11 AM - 2 PM: Peak PMD hatch window — prime time for both nymphs and dry flies; watch for rising fish in the feeding lanes.
- 4 PM - 7 PM: Evening caddis activity along the banks; fish dries and emergers before afternoon storms push through.
Guide's Tip
From the benchWith flows at 1,520 CFS, the Bighorn's classic feeding lanes are well-defined — focus your drifts along the seam between fast and slow water at 2–4 ft depth, keeping your indicator set so your flies tick the bottom occasionally. The PMD hatch is your main event today, so watch for the first rises around 11 AM and be ready to switch from nymphs to a dry the moment you see consistent surface activity. With afternoon rain showers possible and NW winds building to 12–18 mph, get your best dry-fly fishing done before 2 PM and then lean back on nymphs through the evening caddis window. Wade anglers should work the gravel flats below the dam access; float anglers will find the most consistent action in the first 10 miles.
Main Species
Brown Trout
Rainbow Trout
Mountain Whitefish
